What is spleen?functions and embryonic development of spleen along with disease related to spleen

SPLEEN

Introduction

Spleen is a very vital and crucial organ that is present in the bodies of all vertebrates it's very vital organ for the body as it is involved in old red blood cells recycling along with the storage of platelets as well as white blood cells along with this it is also involved in immunity and immune system and also responsible for regulation and production of various types of lymphocytes. In case of humans spleen is present in the left upper quadrant of the abdomen and lies between the 9th and 11th ribs on left side and is along the axis of the 10th rib. Spleen is underneath the left part of the diaphragm and has a smooth surface that faces diaphragm. Spleen is also protected by the rib cage to prevent it from any physical trauma as rib cage protects other vital organs present in the thoracic cavity. spleen is generally fist shaped and normally one cannot feel it by touching it from outside the body unless it's size is abnormally increased due of any reason.If we look at the history of the spleen than a very interesting history is associated with it. If we look into the medieval times than hot temper or anger was associated with spleen. But as the time passed we learned that venting anger was not the function of spleen instead it plays a very important role in the body. Spleen is a relatively smaller organ but it is the largest organ of the lymphatic system. Despite of its all functions and integral role in the body if due to any reason it is removed from the body (splenectomy) a person can still carry on its life but it would not be as same as without it but a person can survive because other tissues of the lymphoid system such as lymph nodes and Liver steps in and carry out spleen's functions but these cannot release spleen.As spleen is a component of immune system not the whole immune system itself so therefore because of any reason if spleen is removed from a person than he can live but life of such a person would not be same as before as there would be a decrease in the immunity of such a person and on the other hand spleen also plays a very important role in fighting bacteria and infections so such a person whose spleen is removed would be more prone to infections. Spleen is basically made up of two different types of tissues that are given below and both of the tissues perform different and unique features as compared to each other these two tissues are

• white pulp tissues ( helps in immunity and immune system )
• red pulp tissues (responsible for blood filtration ) 

the origin of word spleen comes from ancient Greek. There is a funny and interesting fact that in medieval times people related spleen to anger and thought that spleen was the source of anger but its a myth and a wrong concept because don't have any relation or anything to do with anger and emotion it is just involved in the recycling of old red blood cells and also involved in the immunity of the body. Spleen is the center of activity of the mononuclear phagocytes system and is analogues to a large lymph node and its absence causes a predisposition to to certain infections. In near to middle of the spleen there is a long fissure that is the point of insertion of the splenic artery and also the splenic vein this is also the point of attachment for the gastrosplenic ligament for nerves and other lymphatic vessels other openings are also present. In spleen blood is supplied by both short gastric artery and the splenic artery. As spleen is a part of the lymphatic system therefore it possess only efferent lymphatic vessels.If we talk about the weight height and length of spleen than we can say that spleen in a healthy adult is about 2.8 inches to 5.5 inches in length and its weight is about 150 - 200 grams. There is a very useful formula rule or shortcut too remember the dimension of the  spleen and ithe formula is 1x3x5x7x9x11 rule. this rule is as that spleen is 1 by 3 by 5 inches and its weight is about ( 7 oz ) and lies between the 9th and 11th ribs spleen is divided by a ridge into two regions that are

• anterior gastric portion
• posterior renal portion

gastric portion is directed forward upward and toward the middle is broad and concave and is in contact with the posterior wall of the stomach. Below this it is in contact with the tail of the Pancreas. The renal surface is directed medialward and downward. Is is somewhat flattened considerably narrower than the gastric surface and is in related with the upper part of the anterior surface of the left kidney and occasionally with the left Adrenal gland.

embryonic development of spleen

Spleen is unique in respect to its development within the gut. Spleen is derived from the mesenchymal tissue. Specifically spleen forms within and form the dorsal mesentary however it still shares the same blood supply the celiac trunk as the foregut organs. AT the initial embryonic stage spleen plays its one of the most important role and it is the formation of blood but this property of spleen is lost with the embryonic development and lymphoid precursor cells migrate into the developing spleen. Vascularization of spleen arises initially as branches from the dorsal aorta then the celiac trunks largest branch. During the fetal period spleen appears lobulated but these lobules normally disappears before birth. In spleen cells required for its embryonic blood formation function arises from the yolk cell wall and near dorsal aorta. Spleen generates both red and white cells in the second trimester.

functions of the spleen

Bascially spleen plays a very important role in the body such as with related to blood cells blood filtration immune system and many more. If we talk about functions of spleen at embryonic developmental time than at that time it have one of the major function and that is blood formation up until the fifth month of the gestation. Spleen spleen is also involved in formation of very important compounds that helps in immune system such as

• opsonins
• properdin
• tuftsin 

spleen is also responsible for the storage of red blood cells as spleen stores roughly 30% of the red red blood cells and release them when needed. In humans about 240 ml of red blood cells is held in spleen almost all the time and releases it in conditions such as hyperemia and hypoxia. It can also also store platelets as well well as it is also responsible for the storage of the lymphocytes. In spleen the globulin portion of the hemoglobin is degraded to its basic constitutive amino acid and the heme portion of the hemoglobin metabolized to bilirubin which is than removed in the Liver. Spleen primary job is the filtration of the blood as blood flows into the spleen. It also performs a quality control service detecting any red blood cells that are old or damaged. Once the red blood cells are broken down the spleen stores useful leftover products such as iron which  eventually returns to the bone marrow which than makes hemoglobin. Spleen also plays role in the immune system in such a way that it detects any type of pathogens or harmful materials in the blood and produces white blood cells in response to that pathogens to defend the body against them around one quarter of lymphocytes are stores in spleen at any point of time spleen is also responsible for the clearing out of old platelets it and spleen also acts as a storage house for platelets.

diseases related to spleen

If anything interferes with the normal functions of the spleen makes any type of damage in its structure or makes any problems in its secretion can become the cause of spleen related disorders or diseases and these may occur if spleen ruptures enlarges platelets count lowers in the body or if there is any disturbance in the structure of red blood cells and there can be many more problems that we will discuses below in detail. To detect any problem in the spleen we perform various test that are as following 

• ultrasound
• computed tomography
• magnetic resonance imaging
• bone marrow biopsy
• Liver and spleen scan
• physical examination 

where as the some techniques that we perform as spleen treatment are as following

• vaccinations 
• splenectomy

if we talk about the diseases related to spleen than many diseases are given below

• enlarged spleen
• lacerated spleen
• sickle cell disease
• thrombocytopenia
• accessory spleen
• spleen deflation
• asplenia
• splenic infraction
• hyaloserositis
• hyperslenism

enlarged spleen

Enlargment of the spleen is also known as splenomegaly it may be caused by following reasons 

•  sickle cell anemia
•  leukemia
•  Gaucher's cyst
•  glandular fever 
• Cirrhosis
• pressure on or blood clot in the veins of the spleen or Liver any more more conditions
• a large abscess a pus filled cavity
• sarcoidosis
• rheumatoid arthritis
• glycogen storage disease
• Hodgkin's disease

Some of the symptoms of the enlarged spleen are as following

• pain in upper left abdomen 
• anemia
• bleeding 
• fatigue
• feeling full 
• being unable to eat a large meal

ruptured spleen

Spleen is very vulnerable to injury a ruptured spleen can cause serious life threatening internal bleeding after a injured of spleen it may also may rupture and this rupturing after injuring may occur immediately after injury or in some case it may take days weeks after am injury. Usually rupture in the spleen occurs due to any type of physical trauma such situations cases a breakage in the spleen's surface and lead to severe internal bleeding some of the common symptoms of the ruptured spleen are as following

• pain to touch upper part of the abdomen 
• pain in left shoulder 
• pain in left chest wall
• state of confusion 
• lightheartedness

Certain diseases such as malaria infectious mononucleosis make a ruptured spleen more likely because they causes the spleen to swell and the protective capsule to become thinner. In a case when there is a ruptured spleen than we treat such a condition by either repairing spleen removing spleen or removing part of the spleen that is injured human can live without their spleen but those without one may be more susceptible to infections 

sickle cell anemia

Sickle cell anemia is a disorder of the blood caused by an inherited abnormal hemoglobin the abnormal hemoglobin causes distorted red blood cells. sickle cell anemia is caused as a result of point mutation in change of glutamic acid to valine at position 6 from the N terminal end in hemoglobin beta chain. It alters the tertiary structure of hemoglobin anf it fails to carry oxygen. Sickle cell anemia is a inherited form of anemia in which the abnormal red blood cells block the flow of blood through vessels and can also lead to the organ damage as the normal shape of the red blood cells id biconcave and sickle cell anemia can also cause a damage to the spleen people with such a disorder need immunization to prevent illness and helps their spleen to fight against certain diseases, Sickle cells block the blood flows through blood vessels immediately deprive the affected organ of blood and oxygen in sickle cell anemia blood is crucially low on oxygen and oxygen deprived blood can damage nerves and also the organs in the body such as kidney Liver and also spleen. Some of the common symptoms related to sickle cell anemia are as following 

• pain
• fatigue
• anemia
• bacterial infections
• dactylics
• artgritis
• Lungs and heart injury 
• leg ulcers
• eye damage
• aseptic necrosis

thrombocytopenia

Ii is a condition in which an enlarged spleen sometimes stores excessive numbers of platelets as a result of this disease there is a abnormally few platelets circulating in the bloodstream where they belong that lowers platelets count in the body. When you don't have enough platelets in your blood in such a case one's body can't form clots this condition can range from mild to severe. Some of the symptoms of the thrombocytopenia are as following 

• easy or excessive brushing 
• superficial bleeding 
• prolonged bleeding
• bleeding from gums and nose
• blood in urine 
• blood in stool 
• heavy menstrual period

some of the causes as a result of which thrombocytopenia occurs are as following 

• Aplastic anemia
• leukemia
• lymphoma
• May Hegglin syndrome
• mumps
• Rubella
• Epstein Barr virus
• radiation 
• lupus
• idiopathic thrombocytopenic purpura
• disseminated intravascular coagulation 
• hepatitis C

accessory spleen

It is a condition in which people have a second spleen along with a normal spleen that is around 1 cm in diameter about 10-15 % have an additional spleen generally this causes no problem and is still considered normal accessory spleen is a small splenic nodule extra to the spleen that is formed in the early embryo formation. Poly splenic is a congenital disease that is manifested by multiple small accessory spleens rather than a single full sized normal spleen. These accessory spleen are non functional. 

asplenia

Asplenia refers to a non functional spleen which may be congenital or caused by a traumatic injury splenectomy diseases. Hyposplenia reefers to a partially functional spleen these conditions may cause a modest increase in circulating white blood cells and platelets a diminished response to some vaccines.